From a consumer perspective, dispensers which automatically provide a metered dose of a foaming liquid composition are highly desirable. Delivery of a foamed liquid composition, e.g., a soap, a cleaning composition, a topical treatment composition, a foamed or foamable composition for application to the epidermis, hair or other part of a human or animal body is advantageous in several respects. The foam structure of the foamed liquid composition provides for a mass of the liquid composition with an expanded volume due to the air or other gas entrained within the foamed liquid composition which provides a perception of a greater mass of product being delivered, and at the same time the foamed liquid composition is frequently easier to deliver to a surface e.g., a hard surface, an epidermis, etc. Furthermore the use of a foamed liquid composition often accelerates the spreading and distribution of the foamed liquid composition onto a surface.
Currently dispensers which provide a metered dose of a foaming liquid composition are often manually operated pump-type dispensers which requires that a user must necessarily compress a part of the pump, in order to deliver a dose of foamed liquid composition. Such requires physical contact between the user and the dispenser, which is not always desirable. Many common maladies, e.g., influenza virus, rhinovirus, may be undesirably transmitted between users of such a manually operated pump-type dispenser which increases the incidence and spread of diseases. Furthermore, manually operated pump-type dispensers also frequently become unattractive in appearance due to repeated physical contact between the user and the dispenser which user while utilizing the dispensed foamed liquid composition provided, rarely or consistently also cleans the pump.
Known to the art are automatic dispensers for the delivery of liquids from a reservoir contained within the said dispenser device, which may be a reservoir for storing liquids prior to their delivery, particularly for dispensing liquid soaps in response to a non-contact interaction with the user, e.g. the use of one or more sensors to determine the proximity of a user. Such “hands free” dispensing devices and refill units useful therewith are generally known to the art, and include those commonly assigned to the proprietor of the instant patent application. Such include the dispenser and refill unit disclosed in PCT/GB2009/002682; a relief valve and a cap assembly as disclosed in PCT/GB2009/002672, as well as the bottle with a tamper proof-cap as disclosed in PCT/GB2009/002678. The entire contents of these patent applications are herein incorporated by reference thereto. While the dispenser and refill unit described in WO 2010/055314 provides certain advantages over other prior art dispensers and while it may be very advantageously used for the delivery of a liquid composition, it is poorly suited for reliably dispensing foaming liquid compositions in the manner provided by the present application, particularly metered doses of a foamed liquid composition.
Thus there is a real and urgent need for further improvements to dispensers for the delivery of a foaming or foamable liquid composition therefrom.